A novel approach to model effects of surface roughness parameters on wear

Engineering surfaces with similar average or RMS roughness exhibit different values of skewness and kurtosis due to different machining processes. As the surfaces evolve during operation and the wear process, the roughness parameters undergo significant changes. To investigate the change in the roughness parameters and their effect on wear rate, it is of significant importance to investigate and simulate deep wear scars. In this study, a novel method to simulate wear on rough surfaces is proposed. The surface is treated as a collection of asperities of different radii at different heights. The method is applied to a linear elastic material model and the contact parameters are calculated using the Hertzian contact theory. Material removal is simulated by a simple truncation model and Archard's wear law is used at asperity level to evaluate wear depth. Surfaces with various values of RMS roughness, skewness and kurtosis are investigated and two distinct wear rates are obtained for each surface, running-in (severe) wear and steady state (mild) wear. It is also predicted that surfaces with high roughness, kurtosis and positive skewness exhibit higher wear rates. This investigation highlights the importance of studying the effects of surface parameters on wear rate and demonstrates that although a linear wear law is assumed at each asperity, a non-linear wear rate of rough surfaces can be obtained computationally, which are similar to trends observed in experiments.